Above two images, September 1st

September 13th

© A. R. Dean

The two outermost primaries have been dropped. In the third image note the prominent black subterminal band on p5. This is a 3cy of known age (tracked from 2W plumage) and is quite advanced in its appearance compared with a similarly aged Herring Gull (with uniformly grey upperparts and coverts and and all-white tail). Having completed their moult and when at rest, with folded wings, 3cy YLG can easily be assumed to be older.